Syringe or like parenteral device

ABSTRACT

A syringe or like device which can be used for the conveyance of parenteral fluids which are to be introduced into or drawn from the body through the skin comprising a tubular body (11) having a forward end (26) and a rearward end (34) where the forward end is capable of receiving a hollow needle (20) to enable the needle to be able to project from the body, the needle (20) slidable relative to the body (11), the body (11) also including a chamber (14) capable of receiving a parenteral fluid and capable of being reduced in volume to expel the fluid contained therein, the needle (20) is capable of being manually retracted into the body (11) by a retracting member (28) such that the chamber reduces in volume to expel the fluid contained therein and such that the needle (20) is retracted to be wholly contained within the body (11). The needle is able to be supported at one end from the body by a plug (16) which is slidably and sealingly received in the body (11). The chamber (14) is located rearward of the plug (16) and the plug is adapted to enable the needle to communicate with the chamber (14) through the plug, a stop (18) provided in the body rearward of the plug (16) to define the rearward end of the chamber (14). The stop (18) being slidably and sealingly received in the body (11) whereby a greater degree of forces required to move the stop (18) than to move the plug (16). The rearward end (34) of the body slidably supporting a slider (38) or axial movement, an external protrusion (40) on the slider (38) for manipulation of the slider to effect axial movement. The retracting member (28) comprising a flexible member secured at one end to the plug (16) and secured at the other end to the slider (38) slidably and sealingly received through the stop (18).

FIELD OF INVENTION

This application is a 371 of PCT/AU94/00618 Oct. 11, 1994

THIS INVENTION relates to a syringe or like parenteral device.

Throughout this specification the term "syringe or like device" shall betaken to include any device which can be used for the conveyance ofparenteral fluids which are to be introduced into or drawn from the bodythrough the skin and shall include within its scope a syringe, acannula, a hypodermic needle, an intravenous infusion line, and likedevices.

BACKGROUND OF THE INVENTION

A primary characteristic of parenteral devices is the provision of asharp hollow needle to facilitate the transfer of fluids to or from thebody. The difficulty created by the presence of such a needle arisesfrom the possibility of injury which may be caused to a user or tomedical staff when using the device, or indeed to any person who may berequired to handle the device before or after use.

Of course, the injury itself does not represent the major concern. Themajor concern arising from the dangers of infection from such injuriesis due to the pathogens which may be present on the needle as a resultof its use. Indeed, it has been proven that a number of viralinfections, notably the HIV virus and hepatitis B, can be transmitted bythe reuse of needles previously used to inject an infected individual.

These dangers have resulted in the development of very careful andsometimes detailed disposal procedures being adopted in institutionswhere such parenteral devices are used. It has also resulted in attemptsbeing made at developing single use parenteral devices that are notcapable of being reused.

However, the disposal procedures adopted by such institutions are notable to be enforced in out-of-clinic situations, such as thosesituations where individuals inject recreational drugs. Further, theusers of recreational drugs are often capable of quite easilymanipulating a so called "one use" syringe to be able to continue usingthat same syringe.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedparenteral device wherein operation of the device in performing aninjection alters the configuration of the device such that the devicebecomes extremely difficult to refill and also to reuse. A furtherobject is to provide a parenteral device having a needle that retractsso as not to be exposed after use.

The present invention provides a syringe or like device comprising atubular body having a forward end and a rearward end, the forward endbeing capable of receiving a hollow needle therein so as to be able toproject therefrom, the retractable needle being slidable relative to thebody, the body also including a chamber capable of receiving parenteralfluid and capable of being reduced in volume to expel fluid containedtherein, wherein; the needle is capable of being manually retractedwithin the body by a retracting means such that the chamber reduces involume to expel fluid contained therein and such that the needle isretracted to be wholly contained within the body; the needle issupported at one end from the body by a plug, the plug being configuredto be sealingly engaged with the internal walls of the body and to beslidable within the body; the chamber is located rearwardly of the plugand the plug is adapted to enable the needle to communicate with thechamber through the plug; a stop is provided in the body rearward of theplug to define the rear end of the chamber, the stop means beingslidable relative to the body and being in sealing engagement with theinternal walls of the body, whereby a greater degree of force isrequired to move the stop than to move the plug; the rearward end of thebody slidably supporting a slider for axial slidable movement, aprotrusion on said slider for manipulation thereof to effect said axialmovement, wherein said retracting means comprises a flexible member,secured at one end to the plug and secured at its other end to theslider and slidably and sealingly received through the stop.

By holding the forward end of the body of the syringe closely adjacentthe skin of the user, the needle may continue to be retracted into thebody of the device during injection such that the sharp end of theneedle is not caused to be exposed whatsoever between insertion of theneedle into the body and completion of the injection.

When using the parenteral device of this invention it thus becomesimportant to use the device accurately to ensure that the dose isdelivered subcutaneously. Thus, the initial retracting of the needlecauses the volume of the chamber to reduce so as to expel the fluidtherefrom, to a point where the plug abuts the stop means. Furtherretraction of the needle then causes the rearward movement of both theplug and the stop means to allow the needle to be fully withdrawn intothe body. A greater degree of force is required to move the stop meansthan to expel the fluid.

The present invention provides an improved parenteral device that allowsfor the complete retraction of its needle during use within the bodythereof. The lack of any externally operable rigid elements which arerigidly connected to the needle and that may allow the re-extension ofthe needle assists in causing the device to be primarily a one usedevice. The construction of the device is simple and cheap and allowsfor relatively easy filling with minimal complexity. Further, it isexpected that as the injection of parenteral fluid and withdrawal of theneedle occurs simultaneously, there may be the additional beneficialeffect of depositing the parenteral fluid throughout the deeper part ofthe needle track. This is expected to provide an advantage in reducingthe pain which may be caused in conventional syringes by the distensionof tissues at the single point of injection and more rapid absorption ofthe fluid.

It will also be appreciated that the dimensions and extent of travel ofthe needle and plug may be optimised for expelling a parenteral fluidinto any body cavity. In particular, the needle may be inserted into avein and retracted along the lumen of the vein as the parenteral fluidis expelled, the chamber being completely emptied before the needle isretracted out of the vein.

According to a preferred feature of the invention, the stop whendefining the rearward end of the chamber is sealingly and slidablyreceived in the body and on completion of the movement of the plug tothe minimum volume position of the chamber, the stop is movable with theplug whereby the stop will be accommodated in a non sealing manner inthe rearward end. The sealing engagement can be effected by forming therearward end of the body with a greater internal diameter than theremainder of the body. Alternatively the cross-sectional configurationof the rearward end may be formed with a portion having a greatertransverse dimension than the diameter of the remainder of the body.This can be achieved by formation of a longitudinal groove in theinternal wall of rearward end of the body. In addition, if desired theplug when at its rearmost position is non sealingly engaged in therearward end of the body. As a further alternative the rearward end ofthe body can have a different cross-sectional configuration to that ofthe body. For example, the body may be of circular cross-section and therearward end may be of square or eliptical cross-section.

According to a further alternative preferred feature of the inventionthe protrusion comprises an axially directed shaft which can take thesame form as the handle of a plunger of a conventional syringe.Alternatively the external protrusion may comprise a radially directedprotrusion extending laterally from the side wall of the rearward end.

According to a further preferred feature of the invention, a protrusionis provided on the interior of the body which is engaged by the sealingsurface of the stop and/or the plug on joint rearward movement of thestop and plug to cause damage to the sealing surface. As an alternativefeature, the protrusion may pierce the stop and/or plug on jointrearward movement of the stop and plug to destroy the sealing integrityof the stop and/or plug.

According to a further preferred feature of the invention, free end ofthe needle is received in a nipple-like element which is provided at theforward most end of the body and whereby manual withdrawal of thenipple-like element away for the body will cause extension of the needlewithin said body, whereby the nipple-like element is capable of beingremoved from the needle. A further feature of the feature, thenipple-like element is provided with a port which is engagable with areceptacle of a parenteral agent such as an ampoule and the opening inthe free end of the needle opens into the port.

According to a further preferred feature of the invention, a resilientmeans is provided between the body and the plug and is associated with atrigger means whereby when the needle is in the extended position theresilient means is maintained in a stressed state and on release of thetrigger mechanism the resilient means is able to move to an unstressedstate and cause movement of the needle, plug and stop to the fullyretracted position.

The present invention will now be described in relation to theaccompanying drawings. However, it is to be appreciated that thefollowing description is not to limit the generality of the abovedescription.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a sectional view of a parenteral device according to a firstembodiment of the present invention with the chamber filled;

FIG. 2 is a sectional view of the embodiment of FIG. 1 during injection;

FIG. 3 is a sectional view of the embodiment of FIG. 1 after the chamberhas been emptied;

FIG. 4 is a sectional elevation of the embodiment of FIG. 1 ready fordisposal;

FIG. 5 is a sectional view of the embodiment of FIG. 1 prior to filling;

FIG. 6 is a sectional view of the embodiment of FIG. 1 at the conclusionof filling;

FIG. 7a and 7b are cross-section view of the axial extension ofalternative embodiments of the invention as shown at FIG. 1;

FIG. 8 is a sectional view of a parenteral device according to a fourthembodiment of the invention;

FIG. 9 is a sectional view of a parenteral device according to a fifthembodiment of the invention;

FIG. 10 is a sectional view of a parenteral device according to a sixthembodiment of the invention; and

FIG. 11 is a sectional view of a parenteral device according to aseventh embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a parenteral device 10 having a body 12 in the formof a substantially tubular barrel 11 which provides a sealed chamber 14between a plug 16 and a stop 18. A sharpened tubular needle 20 is firmlyfixed to the plug 16 and passes through it so as to provide fluidcommunication within the hollow interior of the needle 20 between thechamber 14 and the open end 22 of the needle 20. The needle 20 passesthrough an opening 24 in the forward end 26 of the body 12.

The body 12 further comprises an axial extension 34 which is of tubularconfiguration and is coaxial with the tubular barrel 12 but is ofgreater diameter to provide a step 36 at the junction between thetubular barrel and the axial extension. The stop 18 when in its normalposition bridges the step 36 and is configured to be sealingly engagedwith the bore of both the tubular barrel 12 and the axial extension 34.

The axial extension 34 slidably supports a slider 38 through a pair ofdiametrically opposed slots formed in the side wall of the axialextension. The slider comprises a main portion accommodated within theaxial extension and a protruberance 40 to each side of the main bodywhich extends through the slots. The protruberances provide a handle toenable movement of the slider 38 in the axial extension.

A retracting means in the form of a flexible member 28 is secured at oneend to the rear 30 of the plug 16 and at the other end to the slider 38.The flexible member 28 passes through the stop 18 in sealing engagementtherewith.

The chamber 14 is capable of receiving and containing a parenteral fluidsuch that by moving the slider 40 outwardly within the tubularextension, the plug 16 through its connection to the flexible member ismoved to the rear of the body 12. This serves to retract the needle 20into the main body and also in reducing the volume of the chamber 14 toexpel the parenteral fluid from the open end 22 of the needle 20.

The device 10 is shown in use in FIG. 2 with the needle 20 having beeninserted below the surface of the skin of a person. With the parenteraldevice 10 in this position, where its forward end 26 lies closelyadjacent the skin, the slider 38 may be pulled in the direction of arrowA to reduce the volume of chamber 14 by urging the plug 16 towards thestop 18 to expel the parenteral fluid from the needle 20. As thisoccurs, the needle 20 is being withdrawn into the body 12 of the device10. In this form, the device 10 is preferably configured such that allof the parenteral fluid is expelled from the chamber 14 by the time thatthe open end 22 of the needle 20 reaches point B which is about 5 mmbelow the surface of the skin.

FIG. 3 illustrates the device 10 after all of the parenteral fluid hasbeen expelled from the chamber 14. At this position, the flexible member28 has been pulled through the stop 18 to a point where the chamber 14has been fully reduced in volume and the plug 16 is in contact with thestop 18. On the application of a further force to the flexible member 28the slidable stopping means 18 is urged towards the rear 34 of the body12 such that the entire length of the needle 20 is retracted within thebody 12. FIG. 4 illustrates the device after the needle 20 has beenretracted completely within the body 12. The axial extension 34 providesa region of increased diameter within which the stop 18 is able to bereceived and the plug 16 is caused to enter and in which the plug isloosely received when the free end 22 of the needle lies inward of theopening 24. Since there is no rigid interconnection between the plug 16and the slider 38 it is extremely difficult for a user to realign theplug 16 in the main body and cause the needle 20 to be extended to beable to reuse the syringe. The step 36 provides a sharp reduction indiameter of the bore of the body, so as to provide a well definedshoulder which creates a difficulty in reengaging the plug 16 in thetubular barrel 12. In a second and third embodiment in the invention asshown at FIGS. 7a and 7b respectively the internal cross-section of theaxial extension 34 is formed to have a portion 44 of greater transversedimensions than the cross-section of the tubular barrel 11 such that onthe stop 18 and the plug 16 entering the axial extension 34 the sealingengagement with the internal wall of the body is lost. This increasedtransverse dimension can be achieved by having the axial extensionformed to have the square crosssection as shown at FIG. 7a in relationto the second embodiment or alternatively an elliptical cross-section asshown at FIG. 7b in relation to the third embodiment.

In a fourth embodiment as shown at FIG. 8, sharp projections 48 areformed on the inner wall of the body 12, which are intended to damagethe sealing surfaces of the stop 18 and/or the plug on movement to afully retracted position.

According to a fifth and sixth embodiment as shown at FIGS. 9 and 10respectively, one or more spikes 50 or the like may be fitted to theplug 16 or stop means 18 which will pierce the stop 18, or plug 16respectively on their coming into an abutting relationship to destroythe sealed nature of the chamber 14.

As shown in FIG. 5 and 6 a fresh unused syringe according to each of theembodiments can be provided with a rigid shaped nipple-like element 42which is engaged in the opening 24 and with the free end of the nippleis engaged with the cover seal 48 of the ampoule. The needle is onlypartly retracted into the body such that its free end 22 extends fromthe opening 24. The engagement between the needle is such that theelement 42 can be grasped by the user and pulled to cause the needle tobe pulled to the fully extended position. The nipple-like element is theto receive a "Luer" or similar fitting. In addition, the outer end ofthe needle is configured such that it is able to pierced the seal of anampoule. In each instance the frictional engagement affected with anampoule may be sufficient to facilitate withdrawal of the needle.

The tight fit of the needle 20 within the seal 44 of the nipple ispreferably sufficient to enable the needle 20 with the attached plug 16to be moved to the extended position to cause the chamber 14 to beincreased in volume. This results in the transfer of fluid into thechamber 14 to allow the filling of the chamber. On the full extension ofthe needle and with a greater force on the element 42, the needle 20 iswithdrawn from within the nipple 42 to allow use of the needle when theneedle has reached its outermost position.

In a seventh embodiment as shown at FIG. 11 a spring 52 or a likeresilient device is provided within the space forward of the plug 16between the plug and the forward end of the body 12. For example, aspring that is resiliently compressed to fill the chamber withparenteral fluid and is able to expand under its normal bias to reducethe volume of the chamber 14, may be suitable. A suitable trigger 54 isprovided on the body 2 to hold the spring in its compressed state and toallow the release and subsequent expansion of the spring for injection.The trigger mechanism may be located externally of the body and isoperatively connected with the spring through the forward wall of thebody of the device.

In a further embodiment the resilient device referred to above islocated within a space located rearward of the plug. In this alternativeform, the resilient device can be a spring configured so as to be ableto expand to fill the chamber with parenteral fluid and then resilientlyto contract under its normal bias to reduce the volume of the chamberand expel the fluid. In such an arrangement, the flexible memberreferred to above may be secured to one end of the spring such thatcontraction of the spring moves the one end of the spring rearwardly topull the plug rearwardly. Further, the spring is preferably configuredso as to be able also to displace the stopping means in the same manneras described above. An appropriate trigger mechanism may again beutilised to control the actions of this rearwardly located spring.

Finally, the parenteral device of this invention may be marked withexternal graduations, according to normal practice, to assist inensuring the administration of correct doses of parenteral fluid. Thisnormal practice results in graduations from zero to a suitable numberbeing included from the forward end of the device to the rearward end.

It will be appreciated that there may be other modifications andvariations that may be made to the configurations described herein thatare also within the scope of the present invention.

I claim:
 1. A syringe comprising a tubular body having a forward end anda rearward end, the forward end being capable of receiving a hollowneedle therein so as to be able to project therefrom, the needle beingslidable relative to the body, the body also including a chamber capableof receiving a parenteral fluid and capable of being reduced in volumeto expel the fluid contained therein, wherein; the needle is capable ofbeing manually retracted into the body by a retracting means such thatthe chamber reduces in volume to expel the fluid contained therein andsuch that the needle is retracted to be wholly contained within thebody; one end of the needle supported from the body by a plug which isslidably and sealingly received in the body, the chamber is locatedrearward of the plug and the plug is adapted to enable the needle tocommunicate with the chamber through the plug, a stop provided in thebody rearward of the plug to define a rearward end of the camber, thestop being slidably and sealingly received in the body, whereby agreater degree of force is required to move the stop than to move theplug, the rearward end of the body slidably supporting a slider foraxial slidable movement, an external protrusion on said slider formanipulation thereof to effect axial movement, said retracting meanscomprising a flexible member secured at one end to the plug and securedat the other end to the slider and slidably and sealingly receivedthrough the stop.
 2. A syringe as claimed at claim 1, wherein the stop,when defining the rearward end of the chamber, is sealingly and slidablyreceived in the body and on completion of the movement of the plug tothe minimum volume position of the chamber, the stop is movable with theplug to a rearmost position where the stop will be accommodated in a nonsealing manner in the rearward end of the body.
 3. A syringe as claimedat claim 2, wherein the rearward end has a greater internal diameterthan the remainder of the body.
 4. A syringe as claimed at claim 3,wherein the stop when at its forward most position in the body, islocated at the junction between the rearward end of the body and theremainder of the body.
 5. A syringe as claimed at claim 4, wherein thejunction is formed as a step in the internal wall of the body.
 6. Asyringe as claimed at claim 2, wherein the cross-sectional configurationof the rearward end of the body is formed with a portion of greatertransverse dimension than the diameter of the remainder of the body. 7.A syringe as claimed at claim 6, wherein the plug, when at its rearmostposition, is non sealingly received in the rearward end of the body. 8.A syringe as claimed at claim 6, wherein the external protrusioncomprises an axial directed protrusion.
 9. A syringe as claimed at claim6, wherein the external protrusion comprises a radially directedprotrusion.
 10. A syringe as claimed at claim 6, wherein the stop, whenat its forward most position in the body, is located at the junctionbetween the rearward end of the body and the remainder of the body. 11.A syringe as claimed at claim 6, wherein a protrusion is provided withinthe body to pierce the stop on joint rearward movement of the stop andplug.
 12. A syringe as claimed at claim 6, wherein the free end of theneedle is received in a nipple-like element at the forward most end ofthe body whereby manual withdrawal of the nipple-like element away fromthe body will cause extension of the needle, said nipple-like elementbeing removable from the needle.
 13. A syringe as claimed at claim 2,wherein the plug, when at its rearmost position, is non sealinglyreceived in the rearward end of the body.
 14. A syringe as claimed atclaim 2, wherein the external protrusion comprises an axial directedprotrusion.
 15. A syringe as claimed at claim 2, wherein the externalprotrusion comprises a radially directed protrusion.
 16. A syringe asclaimed at claim 2, wherein a protrusion is provided on the interior ofthe body which is engaged by the stop on the joint rearward movement ofthe stop and plug to cause damage to the sealing engagement between thebody and the stop.
 17. A syringe as claimed at claim 2, wherein aprotrusion is provided within the body to pierce the stop on jointrearward movement of the stop and plug.
 18. A syringe as claimed atclaim 2, wherein the free end of the needle is received in a nipple-likeelement at the forward most end of the body whereby manual withdrawal ofthe nipple-like element away from the body will cause extension of theneedle, said nipple-like element being removable from the needle.
 19. Asyringe as claimed at claim 18, wherein the nipple-like element isprovided with a port which is engagable with a receptacle of aparenteral agent and the interior of the needle communicates with saidport.
 20. A syringe as claimed at claim 2, wherein a resilient means isprovided between the body and the plug and is associated with a triggermeans, said resilient means being in a stressed state when the needle isextended and whereby release of said trigger enables movement of theresilient means to an unstressed state, movement of the needle, plug andstop of the fully retracted position.
 21. A syringe as claimed at claim2, wherein a protrusion is provided on the interior of the body which isengaged by the plug on the joint rearward movement of the stop and plugto cause damage to the sealing engagement between the body and the plug.22. A syringe as claimed at claim 2, wherein a protrusion is provided onthe interior of the body which is engaged by the stop and the plug onthe joint rearward movement of the stop and plug to cause damage to thesealing engagement between the body and the stop and the plug.
 23. Asyringe as claimed at claim 2, wherein a protrusion is provided withinthe body to pierce the plug on joint rearward movement of the stop andplug.
 24. A syringe as claimed at claim 2, wherein a protrusion isprovided within the body to pierce the stop and plug on joint rearwardmovement of the stop and plug.